Comminuting mill



Au@ a2 92@ y www? R C. NEW/HOUSE COMMINUTING MILL Filed April '7 1921. 2Sheets-Sheet l @wv/Mm @2&1 l fw A@ 12 m@ @www R. c. NEW/HOUSECOMMINUTING MILL Filed April '7. 1921 2 Shees-Sheet B Patented Aug. 12,1924.

UNITED STATES PATENT OFFICE.

RAY C. NEWHOUSE, 0F WAUWATOSA, WISCONSIN, 'ASSIGNORIO 1ALLIS-(iB ALMERSMANUFACTURING COMPANY, OF MILWAUKEE, WISCONSIN, A. CORIPORATION OIEDELAWARE.

COMMINUTING MILL.

Application led April 7, 1921.

To all 'whom t may concern:

Be it known that RAY C. NnwHoUsn, a citizen of the United States,residing at VVauwatosa, in the county of Milwaukee and State of1kWisconsin, has invented a certain new and useful Improvement inComminuting Mills, of which the following is a specitic-ation. l

This invention relates in general to improvements in the art of reducingmaterials such as mineral, hard animal or vegetable substances, byimpact and abrasion, and relates more specifically to. improvements inthe construction and operation of rotary drum mills for comminutingmaterials with the aid of a plurality of tumbling. bodies such as balls,pebbles, rods and the like.

An object of the invention is to provide a comminuting mill which issimple in construction and eiiicient in operation.

It has been found in the operation of tube mills, ball mills, rod millsand the like, that considerable available energy is ordinarily wasteddue to Athe cushioning of the tumbling comminuting bodies, bythematerial which is in pulverulent condition. rl`his tine materiallodges upon the comminuting bodies and packs about the larger particlesof material whichrequire further reduction, thereby preventing thecascading and tumbling comminuting bodies from effectively pulverizingthe larger particles of the charge.

In order to make available this energy which is ordinarily wasted due tothe cush ioning effect produced by the tine particles ofmaterial, thepresent invention contemplates removal of the tine material from thecharge, at one or more points along the mill. The invention alsocontemplates return for further reduction, of the relatively largeparticles of material which are discharged from the mill during theprocess of elimination of the fines. y A

A further object of the present invention is to provide a mill whichwill deliver eX- ceedingly uniform and line material at the finaldischarge. Another object of the invention is to provide a simple andcompact comminuting mill in which the parts which are subjected toexcessive wear, are readily stages of the mill.

Serial No. 459,332.

accessible forinspection and renewal. An additional object of theinvention is to provide a compound or multi-stage comminuting millhaving screening means of ample capacity between the successivegrinding` 55 The invention further contemplates the provision of otherimp rovements in construction and operation of mills of thegeneralchavracter referred to, whereby the cost of manufacture isreducedjto a minimum and the eiiiciency of operation is increased to amaximum.

A clear conception ot several embodiments of the invention and of theoperation of devices constructed in accordance therewith, "3 may be hadby referring to the drawings accompanying and forming a part of thisspecification, in which like reference char acters designate the same orsimilar parts in the various views.

Fig. 1 is a somewhat diagrammatic central vertical' section through arotary combination comminuting mill embodying means for separating thematerial which has been suiticiently reduced in the first grind- 75 ingstage, from the oversize; the mill being provided with means fordelivering the separated material ,to the second stage for nal reductionand with other means for returning the oversize material to the firststage for further reduction. f..

Fig. 2 is an enlarged transverse vertical section through thecombination comminut-` ing mill, part of the section being taken throughthe mill division head, 'and another part being taken in front of thedivision head with reference to the direction of flow of the materialthrough the mill. y

Fig. 3 is an enlarged transverse vertical section through thecombination comminut.- 'U ing mill, the sect-ion being taken through theinstrumentalities for returning material which requiresfurtherreduction, to the second stage of the mill. p

Fig. 4f is a purely diagrammatic illusa tration of a rotary combinationcomminuting mill provided with means for introducing material to themill at a point intermedi ate its ends.

Figs. 5 to l1 inclusive are purely dialoo materials, which may beutilized to ad` grammatic illustrations disclosing various combinationswith respect to the flow of Vantage with mills constructed in accordancewith the present invention. j v' The rotary combination or two-stage.comminuting mill disclosed. in detail in Figs.

1 to 3 inclusive, comprises in general a rotary drum orshell 1 which mayhave uni'-,v

form diameter throughout its. length, the shell 1 being provided withlfeed and discharge end heads 2, 3 respectively, and having therein apartition or division head 4 which divides the shell 1 .into successivecoarse and fine grinding chambers 5, 6 respectively, these chambersconstituting the stages of the mill. The mill is rotatably mounted insuitable trunnion bearin 7, 8 located in proximity to the 'end 'head 2,3 respectively, Vand is adapted to be continuously rotated about itshorizontal center line v at a desirablespeedvby means of power appliedto a driving one end of themill.

The preliminary or coarse' grinding chamber 5 is lordinarily filled tonear the gear 9 associated with horizontal center line of the shell 1with' relativel 'large freely tumbling comminut-v 10, 11 are free totumble and cascade within the chambers 5, 6, and are preferably lforme-dof material which will effectively resist impact and abrasion. Thebodies- 10,

11 may assume a 'variety of forms and may.

in some cases be shaped as rods extending substantially the entirelength of the chamber within which they are located. VThe raw materialis fed into the coarse grinding chamber 5 through an inlet trunnion 70.

' lVithin the chamber 5 the material is partially reducedby the actionof the large comminuting 'bodies 10, the partially reduced materialwhich is of'suficient fineness to pass through the holdback plate 19 andscreen 14, being delivered to a receptacle 17 located below and entirelyloutside, of the mill. From the receptacle below the mill, vthe materialwhidh has been discharged from -the first grinding stage through thescreen 14, isV delivered vto the fine grinding or finishing chamber 6vby means of a pair of return scoopsi'l formed as shown in Fig. 3. Thematerial thus de livered to the fine grinding or second stage, isfurther reduced in the chamber by the action of the tumbling comminutingbodies 11. The finally 'reduced materialv is eventually delivered fromthe finishing chamber through a discharge screen 26 ,and 'into the' pathof elevating vanes '12 which automatically discharge the fine materialfrom y ing plate 19 preferably'formed in sections,

an'imperforate Wall disposed parallel to the plate 19, a plurality ofradial ribs 23 which divide the space between the plate and wall into aAseries of chambers 22 communicating directly with the coarse grindingchamber 5 through perforations in the plate 19, an annular sizing screen14 completely surrounding the mill and spaced therefrom to form anannular screening chamber located outside of the shell but communicatingwith the chambers 22 through radial openings 20 in the shell 1,diametrically opposite re-. -jects return vanes 13 having adjacentconducting passages which are segregated from the'chambers 22, scoopplates 21 connecting the return vanes 13 with the screen 14, and returnopenings 25 extending from the vanes' 13 through a central projectingportion 18;which extends away from the par-V tition 4 and inwardlytoward the feed end of the mill. The material delivered from the coarsegrinding, chamber through the perforations in the holdback plate 19,drops by gravity through the openings 20 and upon the annular sizingscreen 14. As this vmaterial'slides along the inner surface of thescreen 14 during rotation of the mill, the relatively fine materialpassesthrough the vscreen perforations and drops into the receptacle 17below. The scoop lplates 21 during each half revolution of the millcatch the oversize particles of material which have passed through theperforations in the ho-ldback plate 19 but which are too large topass'through'the screen 14, and deliver'these oversize particles to thevanes 13 which periodically. shoot the collected batches of oversizematerial back into the medial portion of the coarse grinding chamf ber 5throu h the return openings 25, for' further re uction by thecomminuting bodies 10. The inwardly extending portion 18 of the divisionhead 4 besides serving toQ provide passages for conducting the oversizeinto a medial portionof the chamber 5 and remote from the lplate 19,serve" to throw the relatively large comminuting bodies 10 into themedial portion of the` coarse'grinding chamber and away from the plate19 vand the openings 25. By thus preventing th'e large tumblingcomminuting bodies l0 from lodging in front of the plate 19, thematerial is permitted to pass through this plate with least obstructionthereby 'enhancing the capacity of the mill. A furtherv lrlO advantagein constructing the inwardly ex-l tending portion 18 in the manner shownis that, as the comminuting bodies 10 are thrown into the medial portionof the coarse grinding chamber 5, the larger of the bodies tend to rollfurther than the smaller, so that there is a classication of thecomminuting bodies 10, resulting in grading the size of the comminutingbodiesin proportionfwith the size of the material being reduced. Theshooting of the oversize mate-v rial into the medial portion of thegrinding chamber ca uses'it to be further acted upon by the comminutingbodies before it can again pass through the plates 19.

rI he material delivered to the receptacle 17 may in some cases bederived from other sources than the coarse grinding chamber 5, and mayalso in some instances be classified in order to remove therefrom thatportion which requires no further reduction. In the form of milldisclosed in Figs. 1, 2 and 3, all of the material Which is deliveredfrom thev screen 14 is eventually returned to the mill by means of therevolving scoops 16. These scoops 16 during rotation of the mill,intermittently pick up batches of material from Within the receptacle 17and deliver this material into the end of the finishing chamber 6 remotefrom the discharge end of the mill, through nozzles or injectors whichhave delivery7 passages so movable and directed that the material fromWithin the finishing chamber 6 will not return to the scoops 16. Theportion of the mill in proximity to the division head 4 and the scoops16 may be provided with a suitable removable vhousing or guard 24 asshown.v

This guard is made readilyv removable in order to permit access to thescreen 14 and the scoops 16. The operation of the mill disclosed inFigs.v 1, 2 and 3 should be readily apparent from' the foregingdescription.

It Will be noted that the return scoops 16 may also be employed toinject other materials than that delivered from a preced ing stage ofthemill, to the interior of the mill at any point intermediate its ends. Inthe diagram designated as Fig. 4, the scoops v16 are adapted to injectmaterial to a mill of the two-stage or combination type from a trough77, at a point intermediate the ends of' the finishing chamber 6. Inthis particular mill the division head 40 comprises a combined holdbaclr and sizing screen 19 through Which the material discharged fromthe coarse grinding chamber 5 is delivered into the path of revolvingelevating vanes 33 Which convey material thus elevated into the inletlend of the second stage or finishing chamber 6 through central dischargeopenings 35. When the material thus admitted to the finishing chamber 6has been further reduced to a. sufficient extent.v it may be desirableto admit other matial to the mill from an outside source such as thetrough 77 for the purpose of thoroughly mixing it with the comminutedmaterial, and possibly also in order to pulverize said added material.The scoops 16 provide m'mple and efficient means for thus admittingadditional material to the mill. Material thus added is intimately mixedwith the charge Within the mill during its travel from the scoops 16 tothe discharge trunnion 80. It will be understood of course that the milldisclosed in Fig. 4 should be provided with the usual dischargemechanism and with other details of construction necessary to completethe structure. The scoops 16 may be located at any desired point orpoints along the mill and may be utilized to intro# duce variousmaterials into the mill.

Referring specifically to the material flow diagrams illustrated inFigs. 5 to 11 inclusive, it Will be noted that in each of these figuresthe material delivered Vfrom the first sizing screen 14 is dischargeddirectly to a classifier 117 as indicated by the floivline 31. In thedevice illustrated in Fig. 5, the fine material which is separated fromthe oversize in the classifier 117 is finally discharged as indicated bythe flow line 30. The oversize material is delivered into the finishingchamber 6 by means of the scoops 16 as indicated by the flow line 3:2.From the finishing chamber 6 the finally reduced material is deliveredthrough the discharge trunnion 80, this finally reduced material in somecases requiring no further classification or reduction.

In the diagram designated as Fig. 6, the material passing through thescreen 14 as indicated by the flow line 31 is mixed with the materialdelivered from the fine grinding chamber 6 through the dischargetrunnion 8O as indicated by the return flow line 34. The mixture ofmaterials is delivered -to the classifier 117 wherein the sufficientlycomminuted material is separated from the oversize and the finishedproduct is discharged as indicated by the flow line 30. The oversizematerial from the classifier 117 is returned to the mill and isdelivered into the fine grinding chamber 6 for further reduction.' lViththis arrangement the product finally delivered as indicated by the flowline 30 will be exceedingly uniform since the classier 117 will alsoremove particles passing through the trunnion 80, which require furtherreduction.

In the diagram designated as Fig. 7 Athe material delivered from thesizing screen 14 as indicated by the flow line 31, passes directly tothe Aclassifier 117 which separates the oversize from the material whichhas been sufficiently reduced, finally discharging the latter asindicated by the flow line 30. The oversize from the classifier 117 isreturned to the mill and delivered into the 1 finishing chamber 6 bymeans of the scoops 16 as indicated by the flow line 32. After havingbeen further reduced in the finishing chamber 6, the material isdelivered from the mill through the discharge trunnion SO found.advantageous to apply the presenty and is mixed with the fine materialdelivered from Athe classifier 1 17 as indicated by the vflow line 34.

When reducing materials having certain characteristics or whenexceedingly fine and unlform fina-l product 1s desired, it may beinventionv to mills having more than two grinding stages, as shown inFigs. 8 to `11 inclusive. In each of these diagrams, the mill is dividedinto vthree successive coniminuting chambers 5, 39,- Glvhavingcomminuting bodies of graded' sizes therein.

While these figures disclose mills havingA three successive chambers, itwillbe obvious that more'chambe'rs may beprovided `if desired, by merelyinserting more division heads 4. .Y In the diagram. designated as Fig.8, the material deliveredl from the coarse grinding chamber 5 past thefirst sizing screen 1 4 as indicated 'by the flow line 31,l passesdirectly vto the first classifier 117.- In the first classi vfier 117,the fine particles some ofwhicli may require further reduction, areseparated from the larger particles, andare sent to the secondclassifier as 4indicated 'by the fiow line 3 0. The larger particlesdelivered from the first classifier 117 are'returne'd to-the mill andare introduced into the intermediatefgrinding chamber 39v by means ofthe first`set of scoops 16 vas indicated by the return flow.

line 32.A After having been further reduced in the intermediate sta e,the oversize from the rst classifier 117 is delivered past the secondsizing screen 14 to the second classi fier 17 as indicated by the flowline 36. Thel finished product is delivered fr om the second classifier117 as indicated by the flow line 38, while the oversizejfrom. thisclassi-v material delivered from the coarse grindingchamber 6 past `thefirst sizing screen 14 as indicated bythe fiow line I31', passesvdirectly to the single classifier 117. The

fine material discharged from the classifier 1-17 is sent directly tothe finishing .chamber 6 as indicated -by the flow line 30, While the,

oversize from the classifier is sent'to the intermediate chamber-39 asindicated -by the fiow vline 32, for further reduction. The materialdelivered from the intermediate stage gast the second sizing screen 14asindicate by the flow line 36, is mixed Withthe fine product deliveredfrom the classifier 117,

and is likewise returned to the mill and delivered into the finishingchamber 6, for final reduction. The vfinished product is delivered fromthe chamber 6 through the discharge trunnion' 80.

In the diagram designated as Fig. 10,`the material delivered from thecoarse grinding chamber 5 past the first sizing screen 14 as indicatedby the fiow line 31, passes di'- rectly to the first classifier 117. 'Inthe first classifier 117, the finished product is se arated from thelarger particles, and is. is-v.

charged as indicated by the flou'7 line 30.

The larger-particlesdelivered from the first classifier 117 are returnedto the-mill and are introduced into the intermediate grinding chamber 39for further reduction, by means of the first set of scoops 16 asindicated by the return fiowline 32. After having been further reducedin the intermediate stage, the oversize fromfthe first classifierV 117is delivered past the second sizing screenv 14 to the secon classifier117 as, indicated by the fiow line 36.v The finished product deliveredfrom thelsecond classifier as indicated by the flow line 38, is mixedwith the finished product-from the first classifier as indicated, Whilethe oversize from the second classifier 117 is returned to the mill andis introduced into' the finishing I chamber 6 for final reduction, bymeans'of the second set of scoops 16 as indicated'by the return flowline 37 After being finally A comm'inuted in the finishing chamber 6,.the remaining material is delivered from the mill 'through thedischarge trunnion 80 as indicated by the flow line 34, and is mixedwith the finished product delivered from' the .two vclassifiers 117, asindicated. ,In thediagram designated as Fig. 11, the

material delivered from the coarse grinding chamber 5' past the firstsizing screen 14 as indicated by the flow ,line 31, passes directly `tothe first classifier 117. 4In the first {classifier 117, the relativelyfine 'material yis separated from the larger particles, and

is'sent to the second classifier 117 as indil cated by the flow line 30.The larger particles delivered from the first classifier 117 arereturnedv to the mill and are introduced into the intermediate grindingchamber 39 forfurther reduction by means of the first set of scoops'16as indicated by the return flowline 32." After having been furtherreducedin theintermediate stage 39v thev oversize from the firstclassifieris de livered past the second sizing screen 14 to flow line36. The large particles discharged from the second classifier 117 arereturned the second classifier 117 as indicated by the' to thelmill andare introduced into the finishing chamber 6 forl final reduction, bymeans of the second set ofscoops 16 as indicated by the return fiow line37. After having been further reduced inthe finishing chamber, 6, theremainingmaterial is delivered from the mill through the dischargetrunnion 80 as indicated by the flow line 34, and is also sent to thesecond classifier 114. In the second classifier the finished ,product isseparated from the material introduced thereto from the three sourcesindicatedV by the flow lines 30, 34, 36, and is delivered as indicatedby the flow line 38.

lt Will be noted that by employing the systems Which have beengraphically illus-' trated in Figs. 5 to 11 inclusive, as Well as othersof a similar nature, materials havmill, and an external scoop movablewith said drum to introduce material from said classifier directly intosaid drum remote from said end, a portion of said scoop extendingtransversely of the drum axisv and substantially parallel to the drumperiphery.

4. In a comminuting mill, means dividing therrllitsuccessiverchambers,and means for automatically introducing material directly intmtheperiphery of one of said chambers from an outside source at a point ingvarious characteristics may be redncednintermediate-the-endmoi chamber.

l be obvious that the eiiiciency of a mill constructed in accordancewith the present invention, is increased to a maximum by removing thesuihciently reduced product at one or more points along the mill. Theprovisionof suiiicient screening area at the discharge ends of theseveral chambers, permits rapid delivery of the materials from thechambers thereby producing a mill of large capacity; VThe screensllt'and scoops 16 are readily accessible being located outside of theshell 1. The mill is capable of operation either as a wet or dry millwithout departure from the invention, and is of y exceedingly simple andcompact internal construction.

It should be understood that it is not des' sired to limit the inventionto the exact details of construction and of operation herein shown anddescribed for various modifican tions Within they scope of the claimsmay occur to persons skilled in the art.

It is claimed and desired to secure by Letters Patent: Y

l. ln a comminuting mill, a rotary drum, means forintroducing materialinto an end of said drum, and an external scoop movable vvith said drumto introduce material from an outside souce directly into said drumremote from said end, a portion of said scoop extending transversely ofthe drum axis and substantially parallel to the drum periphery.

2. in a comminuting'mill, a rotary drum,

means for introducing material into an end ci said drum, and an externalscoop movable with said drum to introduce material from an outsidesource directly into said drum remote from said end, said scoo extendingapproximately halt1 Way aroun and substantially parallel to the drumperiphery.

3. ln a comminuting mill, a rotary drum, means for introducin materialinto an end of said drum, a classi er independent of the 5. In acomminuting mill, means dividing v the mill intosuccessivechambersfmeans-for delivering material ventirely free from achamber at one Yside ofsaid dividing means, and means for VVintroducingsaid material directly into the periphery of another cham;

ber from an outside Ysource on the other side.AV

of said dividing means.

6. In a comminuting mill, means dividing the mill into successivechambers, a classiier independent of the mill, means for deliveringmaterial from the mill to said classier at one side of said dividingmeans,

and means for introducing material from" said classifier to the mill atthe opposite side of said dividing means. f

7. In combination, a comminuting mill, means dividing the mill intosuccessive chambers, means for delivering material from one of saidchambers, and means for returning part of said material into theperiphery of another of said chambers from a source independent of saidmill at a point intermediate the ends of said latter chamber.

8. In a combination comminuting. mill, means dividing the mill intosuccessive chambers, means for grading the material delivered from oneof said chambers, said grading means being adapted to deliver the linermaterial free from the mill and to return the oversizeto said chamber,and an external scoop for returning said finer material into theperiphery of another chamber of said mill from a source independent ofsaid mill.

9. In a comminuting mill, a shell forming a chamber, ,a plurality ofcomminuting bodies in said chamber, a'screen in communication With saidchamber, and acentral conveying projection having a tapered outerbounding surface and extending into said chamber for automaticallyclassifying the comminuting bodies adjacent to said screen duringoperation of the mill.

l0. ln a comminuting mill, a shell and a division head forming a:chamber, a screen in said division head and in communication with saidchamber, a plurality of comminuting bodies Within said chamber, and acentral conveying projection having a peripherally smooth tapered outerbounding surface and extending into said chamber for automaticallyclassifying the 'comminuting llC mill for grading materialpassing saidiirst screen, means for returning the rejects from said second screenvto a medial portion of said chamber, and means for introducing thevmaterial passing said secondscreen into a subsequent chamber of themill.

12. In combination, a rotary drum having uniformdiameter throughout itslength, a partition dividing said drum into a plurality of chambers,comminuting means in each of ysaid chambers, means connected with saidpartition delivering reduced material rompne'of said chambers, astationary're-` ceptacle, adapted to receive said reduced material, andmeans connected with said drum for feeding material from said receptacleinto another of said chambers. v

13: 'In'combination, a rotary mill compris. ing a drum `having uniformdiameter throughout its length' and having comminuting means therein,means for removing material from a medial portion of said mill, areceptacle independent of said mill adapt-l edto receive reducedmaterial, and means operable by said rotatingmill for returning materialfrom said receptacle intoa medial portion of said drum.

14. In combination, a rotary mill having comminutingv means therein,means for re- -vmoving material from a medial portion of said mill, areceptacle independent of said mill adapted to receive reduced material,and an external peripheral scoop movable with said rotating mill forreturning material from said receptacle into a medial portion of saidmill.

15. In combination, a rotary mill having a partition forming a pluralityof chambers, comminuting means in each of said chambers, means connectedwith said partition for delivering reduced material from one of saidchambers, a stationary receptacle adapted to receive said reducedmaterial, and means connected with said mill laterally of said partitionfor feeding material from' said receptacle into another of saidchambers,

' 416. In combination, a rotary mill having comminutingmeans therein,means for removing material from a medial portion of said mill, areceptacle independent of said mill adapted to receive reduced material,and mea-ns operable by said'rotating mill for returning material fromvsaid receptacle into a medial portion of said mill located lat, erallyof said material removing means.

17.' In combination, a rotary mill'having 'aplurality of comminutingchambers therein, means connected with said mill for dis-Acharging'reduced material from one of said chambers, a receptacleseparate vfrom said mill for `receiving said reduced mateial, and meansconnected with said .mill for feeding material from said receptacledirectly into anotherof said chambers.

18. In a comminuting mill, a shell forming a chamber, comminuting bodiesin said chamber, a screen in communication with said chamber, and acentral peripherally smoothconveying projection extending into saidchamber coaxially with said mill for automatically classifying thecomminuting bodies adjacent to said sc reen during operation of themill. Y

19. In combination, a rotary mill having a partition forminga pluralitvo chambers,

comminuting ,means in each of saidchambers, means connected with'fsaidpartition for delivering reduced material from one of said chambers, astationary receptacle adapted to receive said reduced material, and ascoop connected with said mill but i11- dependent of said partition forVfeeding ma terial from said receptacle into another vof` of saidchambers.

'20. In a comminuting mill, arotary drum, means for introducingmaterialinto an end of said drum, and a pair ofoppositely disposed externalscoops movable with said drum to introduce material from an outside ysource directly into dia-metrically oppositeV portions of said drumremote from said end, a portion'of each of said scoops extendingtransversely of the drum axis and substantially arallel to thedrumperiphery.

21. n a comminuting mill, a rotary drum having uniform diameterthroughout itsv lengt means for' introducing material into an en of saiddrum, and an external scoop movable' with said ldrum to introducematerial from an outside source directly into said drum remote from saidend, a portion of said scoop extending transversely of the drum axis andsubstantially parallel to the. drum periphery.

22. In a comminuting mill, means dividing the mill into successivechambers, a classifier independent of the mill, means for deliveringmaterial from the mill to said classifier at one side of said dividingmeans, and an external scoo for introducing material from saidclassifier to the mill at the opposite side of said dividing means.

23. In a comminuting mill, a rotary drum, means dividing said drum intosuccessive chambers, a classifier independent of said drum but locatedin proximity. thereto, means for discharging material from one of saidchambers to said classifier, and a scoop movable with said drum forintroducing masaid chambers.

- 24. In a comminuting mill, a rotary drum, movable with said drum forreturning a por a. partition dividing said drum into succestion of saidmaterial from said classifier to sive chambers, a classier independent`of a subsequent chamber of the mill. 3Q said mill located adjacentk tothe periphery In testimony whereof, the signature of the 5 of said drum,mea-ns for delivering reduced inventor is axed hereto. materia-l from eninitial chamber of'saidl drum to said classifier, and an external scoopRAY C. NEVSTHGUSE.

